Booster seat

ABSTRACT

An adjustable booster-type seat having a base  10  for supporting the seat on a flat surface, a riser  12  mounted for height adjustment on the base, a body support  14  having a seat and back mounted for arcuate motion on the riser  12  for changing the angular position of the body support  14  and being adjustable in height by virtue of the adjustability of the riser on the base. A restraint bar  16  is detachably connected to the body support and in turn adjustably carries a tray  18  enabling the tray to be moved toward and away form the back and to be mounted at different angles with respect to the body support  14.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of Applicants' earlierfiled, copending application Ser. No. 10/377,810 filed Mar. 4, 2003,which is a continuation-in-part of application Ser. No. 10/217,702 filedAug. 13, 2002, and which application claims benefit of Applicants'earlier filed provisional application Ser. No. 60/312,016 filed Aug. 13,2001, all of which are incorporated by reference herein in theirentirety.

FIELD OF THE INVENTION Background of the Invention

This application relates to booster-type seats. In accordance with oneaspect of the application, the elevation of the body support may bevaried. In accordance with another aspect of the application, theangular disposition of the body support may be varied. These featuresenable the seat to accommodate newborns who are fed by a caregiver andtoddlers seated at a table. Another aspect of the present application isthe adjustability of the tray with respect to the body support so as tomove the tray toward and away from a child in the seat to accommodatethe child's size, as well as to change the angular disposition of thetray with respect to the body support so that the tray may be placed ina substantially horizontal position when the body support is in itsreclined position. This feature enables a caregiver to place food on thetray while feeding a young child without the food sliding off the tray.Yet another aspect of the present application is the unitizedconstruction of the seat and backrest that comprise the body support sothat the two move together as the body support is adjusted. And yetanother aspect of the present application is the collapsibility of thebackrest so as to accommodated storage and transporting of the seat.This is particularly advantageous in seating that has a unitized seatand backrest.

Additional objects, features and advantages of the present applicationwill become apparent to those of ordinary skill in the art uponconsideration of the following detailed description of preferredembodiments exemplifying the best mode of carrying out the subjectmatter of this application as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a booster seat strapped to achair.

FIG. 1A is a rear perspective view of the booster seat of FIG. 1.

FIG. 1B is a front perspective view of the booster seat of FIG. 1 withthe tray removed and the riser at full height.

FIG. 2 is a schematic side elevational view of the booster seat fullyreclined, the riser at full height and tray installed at a forwardposition.

FIG. 2A is a schematic side elevational view of the booster seatupright, riser at lowermost height and tray installed at a midwayposition.

FIG. 2B is a schematic side elevational view of the booster seatconfigured for storage.

FIG. 3 is an exploded perspective view of the booster seat.

FIG. 4 is a cross-sectional side view of the booster seat shown in areclined position with the riser in the lowermost position.

FIG. 4A is a fragmentary cross-sectional view taken along line 4A-4A ofFIG. 4.

FIG. 4B is a fragmentary cross-sectional view taken along line 4B-4B ofFIG. 4.

FIG. 4C is a fragmentary bottom plan view of a post and socket as seenalong line 4C-4C of FIG. 4.

FIG. 5 is a fragmentary cross-sectional view taken along line 5-5 ofFIG. 4 with the tray and riser catches in their engaged position.

FIG. 6 is a schematic cross-sectional view similar to FIG. 5, but withthe tray and riser catches released.

FIG. 7 is a fragmentary cross-sectional view of the sliding arrangementbetween seat and riser taken along line 7-7 of FIG. 5.

FIG. 8 is a fragmentary cross-sectional detail view of the rack assemblyof FIG. 4 shown on an enlarged scale.

FIG. 9 is a fragmentary exploded perspective detail view of therestraint bar release means as seen along arrow 9 of FIG. 8.

FIG. 10 is a fragmentary cross-sectional detail plan view of restraintbar release mechanism taken along line 10-10 of FIG. 8.

FIG. 11 is a fragmentary cross-sectional detail view of taken along line11-11 of FIG. 10.

FIG. 12 is a fragmentary cross-sectional detail view of the restraintbar arms retention mechanism taken along line 12-12 of FIG. 4.

FIG. 13 is a fragmentary cross-sectional detail view taken along line13-13 of FIG. 12.

FIG. 14 is a fragmentary perspective detail view of the restraint bararms retention mechanism as seen along arrow 14 of FIG. 3.

FIG. 15 is a fragmentary cross-sectional bottom plan view of the traylocking mechanism taken along line 15-15 of FIG. 5.

FIG. 16 is a fragmentary bottom perspective view of the tray lockingmechanism as seen along arrow 16 of FIG. 15.

FIG. 17 is side view of the booster seat with removable legs.

DETAILED DESCRIPTION OF THE INVENTION

The present application relates to booster seats and feeding seats(hereinafter collectively called boosters or booster seats) used bybabies and toddlers.

As shown in FIG. 1, booster seat 1 includes straps 2 for releasablyfastening the booster seat to a chair. The rear of the booster seat isshown in FIG. 1A.

As shown in FIG. 1B, booster seat 1 is adjustable to raise the boosterseat.

As shown in FIG. 2, booster seat 1 is adjustable to recline the boosterseat.

As best seen in FIG. 3, the booster seat includes as its major parts, abase 10, riser 12 and seat and back assembly (sometimes called a bodysupport) 14. The booster seat also includes a restraint bar 16 and tray18. All of these parts typically may be injection molded of suitableplastic material such as polypropylene or other equivalent material. Aswill be evident from the drawings each of the seat and back assembly 14,the riser 12 and the base 10 may be formed as a monolithic member.

The base 10 serves as a bottom support for the seat and back assembly 14and is particularly designed to be placed on a flat surface orientingthe base in a substantially horizontal plane. The riser 12 isessentially permanently connected to the base 10 (forming a baseassembly) although the riser height above the base is adjustable so asto in turn provide adjustment for the elevation of the seat and backassembly 14. The riser 12 also provides an arcuate track 3 forsupporting the seat and back assembly 14 so as to enable the seat to bemoved through an arc of perhaps 30° so that the child in it may beseated in an upright position or in a number of different reclinedpositions. This feature is illustrated in FIGS. 3, 5, 7 and 8. Asexplained below, the embodiment shown provides a number of differentsettings for the seat assembly on the riser that allows incrementaladjustments in the orientation of the seat and backrest assembly ofapproximately 30° so that six or more different angular reclinedpositions are available The restraint bar 16 is removably connected tothe seat and back assembly 14 and will restrain the baby or toddler inthe booster from sliding off the seat and beneath the tray 18. Inaddition, the restraint bar 16 provides the support for the tray 18 andalso provides means for orienting the angular relationship of the traywith respect to the seat and backrest assembly.

The base 10 is shown in FIGS. 1B and 3 to be generally rectangular inshape having a front bar 20, side bars 22 and a rear bar 24. The sidebars 22 and/or rear bar 24 carry one or more anti-skid foot members 26(FIG. 3) to restrain the base from sliding on the surface upon which itrests. Each anti-skid foot 26 is made of material well known in the artthat will optimally prevent the base from slipping when placed onsurface. The restraint bar 16 may take any number of forms and beattached to some or all of the members that define the frame-like shape.The lower surface of the base 10 defines a uniform supporting plane sothat the base will not tip or rock when placed on a flat surface. Thebase 10 also includes a pair of upwardly extending generally verticalside walls 30 and a rear generally vertical wall 29 that in thisembodiment are telescopically received in cavities 31 and 32,respectively, and in the riser 12.

In FIG. 2, the riser 12 is shown in its elevated position on thevertical side walls 30 of the base, while in FIG. 2A the riser is shownin its lowermost position on the base. The height adjustment of theriser on the base is achieved by virtue of three tiers of slots (orholes) 34 formed on the outside surfaces of the side walls 30 thatextend upwardly from the side bars 22 of the base 10. While preferablythree pairs of slots 34 are provided in the walls 30 to provide threeadjustments in the height of the riser, obviously, a different numbermay be employed and the connections may be provided on the inner sidesor the ends of the side walls 30. The slots 34 cooperate with the heightadjustment mechanisms 40 carried on each side of the riser, to supportthe riser on the base at the appropriate elevation for the baby ortoddler to be seated in the booster. FIG. 6 which is a schematiccross-sectional view of one side of the riser shows a handle 42 fixed toa pair of posts 44 that, in accordance with this embodiment, areattached to a pair of tabs 46 that are sized to register with the slots34. As seen in FIG. 7, when the tabs 46 are disposed in one of theselected pairs of slots, they rigidly retain the riser in a fixedposition on the base. It is to be appreciated that the height adjustmentmechanisms are provided on each side of the riser and cooperate with theslots 34 on each side wall 30 of the base 10. In FIG. 6 the cavity 31 isshown adjacent mechanism 52 for biasing the tabs 46 into the slots 34.The cavity 31 receives the side wall 30 of the base. In order to changethe position of the riser 12 on the base, the handles 42 on each side ofthe riser must be pulled outwardly against the biasing mechanism 52 soas to free the tabs 46 form the slots 34. When that is done, the risermay be raised and lowered as desired, and the handles are released whenthe tabs 46 are aligned with the desired pair of slots 34. A connection(see FIGS. 4 and 4C) is made between the riser and base that preventsthe riser from being removed from the base. The riser 12 is free to beadjusted between the various elevations afforded by the pairs of slots34, but the connection between the base and riser prevents the riserfrom being lifted off the base. The mechanism 52 may conveniently bedisposed in the arms 50 of the riser adjacent the cavity 31 thataccommodates the walls 30 of the base. Mechanism 52 includes a lever arm54 which is fixed at one end and has tabs 46 at the other end. One ormore spring-like members 56 biases the lever and tabs into the slots 34(as shown in FIG. 5).

As best seen in FIG. 3, the rear of the riser 12 includes a pair offixed vertically extending tubular members 35 and a second similar pairof fixed vertically extending tubular members 36 at the front of theriser 12. Tubes 37 on the base 10 correspond to tubes 35 and 36 so thatas the riser 12 moves vertically with respect to the base 10 the tubularmembers 35 and 36 telescope into (or out of) the tubes 37 in the base10. As shown in FIG. 3, each tubular member 35 and 36 and tube 37 mayhave a circular or, in the preferred embodiment, a non-circular orfluted type cross-section. This arrangement serves to ensure that theriser 12 moves smoothly with respect to the base 10 without any unduetwisting or angular movement. That is, the telescoping members having afluted or crenulated cross-section, such as with parallel groovesincised on the shaft, providing an antirotational fit between eachtubular member 35 or 36 and tube 37 having a corresponding complimentaryshape. The fluting and corresponding tube shape limits movement to thetelescoping direction and adds stability to the base and riser combinedstructure. Although four tubular member and tube combinations are shownit should be understood that other numbers of such members such as twoor three may be used.

As shown in FIG. 3, the riser 12 has an arcuate platform 60 that forms apair of arcuate tracks 3 supporting the seat and back assembly 14. Asseen in FIG. 6, curved seat edge 79 is supported on the arcuate track 3part of the riser platform 60. At least two seat edges 79 (one on eachside) contact the riser platform 60 at a track 3 and each edge 79 isarcuately shaped to compliment or match the arcuate shape of the riserplatform 60 enabling the seat to slide with respect to the platform 60when reclining or returning to an upright position. The platform 60directly supports the seat and back assembly 14 for sliding motionbetween the most reclined and upright positions of the assembly (seeFIGS. 2 and 2A) and a side rail guide 90 is provided adjacent each guideslot 83 for guiding the seat movement with respect to the riser 12. Asseen in FIG. 6, support 91 on the underside of seat 71 slides, and isguided, with respect to rail guide 90 to maintain seat movement in thedesired arcuate path. When the seat and back assembly 14 is placed onthe riser, the seat arms 62 that are open on the bottom receive the arms50 of the riser as is evident as shown for example, in FIGS. 3 and 6.

The reclining motion of the seat and backrest assembly 14 on the riser,as illustrated in FIGS. 2 and 2A is controlled by the latch or lockingmechanism 80 located in a recess in the riser 12 as shown in FIGS. 3, 4and 8. The rack 82 located in a recess in seat and back assembly 14 iscoupled to the seat bottom 72, and the lever 81 is shown positioned toselectively engage any segment A-F of the rack. The lever 81 is urged ina raised or operative rack engaging position. In FIG. 7 the lever isshown to carry a tab or button 84 on its upper surface in position toengage any of the openings 86 in any of rack segments A-G. The lever 81may be biased by a spring 88 or be formed to have a natural bias toforce tab or button 84 into locking engagement in one of the openings86. To slide the back and seat assembly 14 on the riser, the lever 81must be moved to cause the tab or button 84 to disengage an opening 86in the rack 82, and, preferably after sliding movement to a newposition, when released it automatically reengages the rack to hold theseat and back assembly 14 in a fixed position on the riser 12.

In FIG. 2A the seat and back assembly 14 is shown in the most uprightposition and in FIGS. 2 and 4 the assembly is shown displaced in amaximum reclined position and a first reclined position approximately 5°and 30° respectively from the upright position. As suggested above,additional positions may be set at 0°, 10°, 15°, 20°, and 25° from theupright position. All of the positions are established in the rack 82.Lever 81 and spring 88 assist with insertion and removal of button 84into openings 86 in the rack 82, so that the seat and back assembly 14may be moved to any of the positions established by the rack. Tabs 77(FIGS. 5 and 6) are carried on the bottom of seat and back assembly 14and extend through guide slots 83 in the riser to guide the recliningand return motion of the seat and back assembly 14 with respect to theriser 12 and to retain the seat and back assembly 14 on the riser 12(see FIG. 6). When reclining or returning to upright an underside of theseat slides on arcuate platform 60. Arms 75 extend tabs 77 to reachacross rails 89 (one on each side) on the riser 12. The maximumreclining position and the upright position may be defined when the arms75 reach either end of guide slots 83. Thus, the arms 75 encounteringthe end of guide slots 83 may serve as a stop to limit the reclining orupright positions. Other similar stop members may be provided such as isshown in FIG. 7 wherein a portion 92 of the rear wall of the seat andback assembly 14 is shown engaging a ramp-type stop 85 on the platform60 of the riser 12. Abutments (not shown) may be placed on the riser 12to encounter tabs 77 at the extreme end of their arcuate travel. While apreferred arrangement is shown in FIGS. 3 and 5-8 attaching the seat andback assembly 14 to the riser 12 so as to permit the tilt adjustment andlocking of the assembly, other arrangements may also be used includingtracks, rollers and roller brakes and swing-type linkages, as used inmotion furniture.

FIGS. 9-14 illustrate a preferred embodiment for attaching the restraintbar 16 to the seat and back assembly 14. The restraint bar 16 locks tothe seat and back assembly 14 but may be removed when not in use. Therestraint bar 16 includes a crotch post 100 that carries on its lowerend, a locking plate 102 (see FIG. 9) that is sized to fit within aT-shaped opening 104 in the seat. When inserted in the opening 104(depressing upwardly biased release tab 115) and thereafter movedrearwardly with respect to the seat so that the side edges 106 of thelocking plate 102 pass beneath the flanges 108, the crotch post 100 willbe locked in position. As shown in FIG. 1B, the crotch post 100 extendsdownwardly from and is connected to the front rail 110 of the restraintbar 16. The restraint bar also includes a pair of side panels 112connected to the ends of the front rail 110. The rear ends 114 of theside panels 112 bear against the uprights 124 at the back of the arms 62of the seat and back assembly 14. The lower edge 120 of each panel 112rests on the upper surfaces 122 of the arms 62. The rear end extensions123 are inserted into the openings 156 of seat and back assembly 14 andthe upper portion of the backrest 74 is moved to the FIG. 2A positionthereby locking the rear end extensions 123 to the seat and backassembly 14. FIG. 14 shows one of the rear end extensions 123 about tobe inserted into opening 156 and the upper portion of the seat andbackrest 74 about to close to its upright operable position. FIGS. 12and 13 show one of the rear end extensions 123 in the locked positionwith locking edge 158 of the upper portion of the backrest 74 insertedinto slot 160. Movement of the upper portion of the backrest from itsFIG. 2A position to its FIG. 2B position unlocks the rear end extensions123 (locking edge 158 is removed from slot 160) permitting the restraintbar 16 to be removed. Thus, the restraint bar 16 is held firmly on theseat. As best seen in FIGS. 3 and 9-11 to free the restraint bar 16 fromthe seat, the restraint bar 16 must be moved rearward (to the right inFIG. 11) slightly to remove the front edge 116 of the release tab 115from the channel 117 on the end of crotch post 100. Tab 115 is thendepressed by pressing with a finger or thumb and crotch post 100 may bemoved forwardly so that the side edges 106 of the crotch post 100 arefreed from beneath the flanges 108, and the restraining bar may be slidforward and lifted from the front end by grasping the front rail 110 soas to free the tabs 126 and 127 from the slots 118 and 128 (FIG. 3).This arrangement is clearly shown in FIG. 9. In that figure side edges106 are shown freed from flanges 108 and the locking plate 102 is shownfreed from the T-shaped opening 104 in the seat. While a preferredembodiment for attaching the restraint bar is illustrated, other typesof fasteners may be used to join the bar to the seat and the backassembly.

In FIGS. 1B, 2 and 2A, a series of tray locating holes are shownprovided in the outer sides of panels 112 of the restraint bar 16. (Theholes are visible only in one arm in those figures.) In the embodimentshown, six such holes are provided in each side panel, identified as130A through 130F. The holes 130B through 130F are shown aligned alongthe top edge 132 of the panels, and the hole 130A is shown disposedbelow the plane defined by the centers of the holes 130B through F. Theholes allow the angular orientation of the tray 18 with respect to theseat 71 to be varied and also allow the tray to be moved toward and awayfrom the backrest portions 74, 76 of the seat and back assembly 14.

The tray 18 as shown in FIGS. 1, 2, 2A and 3 includes a flat centraltable surface 140 and a surrounding lip 142 that will assist inretaining items placed on the surface 140. On each side 144 of the tray,a latch mechanism 146 is disposed inside the lip 142 and pivotallysupported on axles 148 (one shown in FIG. 16) mounted in openings 150provided in the flanges 152 on the tray bottom. The pivotally supportedtray latch mechanism 146 in the illustrated embodiment includes a pairof pegs 147 on its inboard side 154 (see FIGS. 15 and 16) that arespaced apart to register with selected pairs of holes 130A through 130Fon the sides of the restraint bar 16. As seen in FIG. 6, compressionspring 149 is compressed to remove peg 137 from hole 130F. Otherwisespring 149 would hold pet 137 in the hole 130F. The pegs are spacedapart the same distance as the space between the holes 130A and 130B,and that spacing is the same as the spacing between pairs 130B and 130D130C and 130E and 130D and 130F. Thus, in the rearwardmost position ofthe tray on the restraint bar 16, the pegs 147 engage in the holes 130Dand 130F but the tray may be incrementally moved away from the backrest(further forward with respect to the seat) by engaging pairs of holes130C and 130E or 130B and 130D. In any of those three alternativepositions, the tray will be at the same angular relationship with theseat and backrest assembly 14 but will simply be closer to or furtheraway from the baby or toddler seated in the seat 71. When the pegs 147register with the holes 130A and 130B the tray will assume a differentangular relationship with respect to the seat and back assembly 14, thatis, as shown in FIG. 2. The tray ordinarily will only be mounted in theholes 130A and 130B when the seat and back assembly is in the mostrearwardly inclined orientation as in FIG. 2. Because in the embodimentshown the seat and backrest assembly 14 is able to tilt approximately30.degree. rearwardly from its upright position, the different angularorientation for the tray with respect to the seat and back assembly ishighly desirable as in that position the tray is more substantiallyhorizontal. That orientation of the seat and back assembly 14 and thetray 18 is ordinarily used for feeding or otherwise attending newborns,and the tray may be utilized by the attendant to carry the food or otheritems, and they will not slide off the tray. The other positions of thetray ordinarily are used when the seat and back assembly is in the moreupright positions. For example, in FIG. 4 where the seat is upright andpartially reclined, the tray is shown connected in its rearwardmostposition utilizing holes 130D and 130F. While in the illustratedembodiment the holes for mounting the tray are provided in the restraintbar, it should be appreciated that the holes may, as an alternative, beprovided in the arms 62 of the seat 71. In that arrangement theconfiguration of the arms and/or the lip or rim 142 of the tray mayrequire reconfiguration to enable the connection between the arms andtray to be made. As yet another modification, the tray may be carried bythe crotch post 100 and a tilt mechanism may be provided to enable theplane of the tray to be varied.

When the booster seat is used by a toddler seated at a table, therestraint bar and tray are not ordinarily used and rather are detachedfrom the body support so that the booster seat is configured as shown inFIG. 3.

It should also be appreciated that in other embodiments the latchmechanism 146 may take other forms. For example, snap type latches, orrack type connectors (such as used to lock the seat and back assembly onthe riser) may be employed for that purpose.

In FIG. 3 the tray is shown to include a pair of toy wells 170 at itsrear corners 172. The wells 170 are designed to receive a variety ofdifferent toys 174 to entertain the baby or toddler seated in thebooster seat.

The upper portion of the backrest 74 of the seat and back assembly 14 isfoldable to the collapsed position. Folding of the upper portion 76 isabout a hinge 78 at the top of the lower portion. In FIGS. 2A, 2B, 4 and14 the backrest 74, 76 of the seat and back assembly 14 is shown to befoldable so as to reduce the overall size of the booster seat,particularly for purposes of packaging, travel or storage. The backrestis shown in FIG. 2A to be in the erect position, while in FIG. 2B thetop portion 74 of the backrest is folded back so as to hang downwardlyfrom the hinges 78 connecting the top portion 74 with the lower portion76 of the backrest. The hinges 78 on each side of the backrest enablethe top portion 74 to fold backward in the manner shown in FIGS. 2B and14. However, a locking member 200 is provided so as to releasablymaintain the upper portion 74 of the of the backrest in the operativeposition of FIG. 2A.

In other embodiments the hinges may be provided intermediate the sideedges, and different types of latches may also be utilized to hold thebackrest in its operative configuration, such as snap-type flangesutilized to hold the restraint bar on the arms of the seat.

In FIG. 17 the booster seat is shown with removable legs 300. Theunderside of the base 10 is provided with connectors such as threadedtype receptors for receiving the threaded ends of the removable legs. Inthis manner the legs may be attached to the booster seat enabling itsuse as a high-chair. Other attachment configurations may be provided toreleasably attach the legs 300 to the booster seat.

From the foregoing description it will be appreciated that numerousother modifications may be made of the illustrated embodiments withoutdeparting from the spirit and scope of the invention. Therefore, it isnot intended that the scope of the invention be limited to theembodiments illustrated and described. Rather, its scope is to bedetermined by the claims and their equivalents.

1. A booster seat comprising, a base, a seat, a curved platform definingan arc on the base supporting a complementary curved portion on asurface of the seat to permit relative movement along the arc, at leastone slot in the curved platform, and at least one tab carried on theseat extending through a slot and engaging a surface of the platform onan opposite side of the platform from the seat and backrest to guide theseat with respect to the base during relative movement along the arc. 2.The booster seat of claim 1 wherein the tab is formed as a monolithicportion of the seat.
 3. The booster seat of claim 1 wherein the at leastone slot comprises two slots and the at least one tab comprises two tabseach carried on the seat and each extending through a slot and engaginga surface of the platform on an opposite side of the platform from theseat and backrest to guide the seat with respect to the base duringrelative movement along the arc.
 4. The booster seat of claim 1 whereinthe at least one slot comprises three slots and the at least one tabcomprises three tabs each carried on the seat and each extending througha slot and engaging a surface of the platform on an opposite side of theplatform from the seat and backrest to guide the seat with respect tothe base during relative movement along the arc.
 5. The booster seat ofclaim 4 wherein one of the tabs and slots is located generallyintermediate the other two tabs and slots.
 6. The booster seat of claim3 comprising two rails on the platform, each rail being adjacent one ofthe slots.
 7. The booster seat of claim 1 wherein the seat ismonolithically formed and has hollow armrests.
 8. The booster seat ofclaim 1 wherein the curved platform is monolithically formed and hashollow side portions that fit within hollow armrests on the seat.
 9. Thebooster seat of claim 1 wherein the seat has hollow armrests, the curvedplatform has hollow side portions that fit within hollow armrests on theseat and the base has side portions adapted to fit within the hollowside portions of the curved platform.
 10. The booster seat of claim 1wherein a latch is coupled to at least one of the curved platform andcurved portion on a surface of the seat and a complimentary holdingsurface is coupled to the other of the curved platform and curvedportion on a surface of the seat.
 11. The booster seat of claim 10wherein the latch complimentary holding surface comprise a rack and atab in complimentary selective engagement whereby the seat and curvedplatform are locked to arrest arcuate movement and unlocked to permitarcuate movement.
 12. The booster seat of claim 1 further comprising aheight adjustment means for adjusting the height of the curved platformwith respect to the base.
 13. The booster seat of claim 1 furthercomprising a stop on the platform adapted to engage a projection on thebottom of the seat and an abutment at the other end of the platformadapted to engage a tab.
 14. The booster seat of claim 1 wherein theplatform is monolithic.
 15. The booster seat of claim 9 wherein, theseat has a seating surface between the hollow armrests and on theopposite side of the seating surface there is provided guides adapted tocontact side portions of the curved platform.
 16. The booster seat ofclaim 1 comprising legs adapted to be removably attached to the base toraise and lower the level of the seat.
 17. A booster seat comprising, abase, a seat, means for supporting the seat and backrest with respect tothe base to permit relative movement along an arc, means for locking andreleasing the seat and backrest with respect to the base in a positionfrom upright to reclined, and means for raising and lowering the seatand backrest on the base.
 18. A booster seat comprising, a base, a seat,a riser on the base supporting the seat and adapted to raise and lowerthe seat, and at least two telescoping members between the base andriser and adapted to limit movement in the telescoping direction. 19.The booster seat of claim 18 wherein the telescoping members have anantirotational fit.
 20. The booster seat of claim 19 wherein theantirotational fit comprises fluting.
 21. The booster seat of claim 18wherein the at least two telescoping members comprise three telescopingmembers.
 22. The booster seat of claim 21 wherein the base has antiskidmaterial coupled to the bottom.
 23. A booster seat comprising, a base, aseat including a seat with a seating surface between spaced hollow arms,a monolithic riser having a curved platform portion defining an arc andsupporting the seat on the base to permit movement of the seat along thearc from an upright position to a reclined position, the curved platformportion being between spaced hollow walls of the riser, arcuate trackson a surface of the curved platform portion of the riser facing theseat, slots in the riser adjacent the arcuate tracks receiving armsextending from the seat and backrest with at least one tab on each arm,each tab engaging a guide surface of the riser facing away from the seatand backrest, the guide surface being shaped to guide the riser and seatand backrest during relative arcuate movement, at least one stop memberon a surface of the riser adjacent the seat and backrest engaging theseat and backrest to arrest arcuate movement in one direction, at leastone abutment member on an opposite side of the riser from the seat andbackrest engaging a tab to arrest arcuate movement in a seconddirection, abutment surfaces on the seat and backrest adapted to engagethe arcuate tracks for guiding movement of the seat and backrest alongthe arc, guides supported on the seat on a side opposite the seatingsurface and facing the riser, the guides adapted to contact the riser, arack in a recess in the seat and a lever in a recess on the riser, thelever being adapted to selectively engage the rack at intervals alongthe arc whereby the riser is locked to arrest arcuate movement andunlocked to permit arcuate movement.